From: Andrea Parri (Microsoft) <parri.andrea@xxxxxxxxx> Sent: Wednesday, November 18, 2020 6:37 AM
>
> __vmbus_open() and vmbus_teardown_gpadl() do not inizialite the memory
> for the vmbus_channel_open_channel and the vmbus_channel_gpadl_teardown
> objects they allocate respectively. These objects contain padding bytes
> and fields that are left uninitialized and that are later sent to the
> host, potentially leaking guest data. Zero initialize such fields to
> avoid leaking sensitive information to the host.
>
> Reported-by: Juan Vazquez <juvazq@xxxxxxxxxxxxx>
> Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@xxxxxxxxx>
> ---
> drivers/hv/channel.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/hv/channel.c b/drivers/hv/channel.c
> index 0d63862d65518..9aa789e5f22bb 100644
> --- a/drivers/hv/channel.c
> +++ b/drivers/hv/channel.c
> @@ -621,7 +621,7 @@ static int __vmbus_open(struct vmbus_channel *newchannel,
> goto error_clean_ring;
>
> /* Create and init the channel open message */
> - open_info = kmalloc(sizeof(*open_info) +
> + open_info = kzalloc(sizeof(*open_info) +
> sizeof(struct vmbus_channel_open_channel),
> GFP_KERNEL);
> if (!open_info) {
> @@ -748,7 +748,7 @@ int vmbus_teardown_gpadl(struct vmbus_channel *channel, u32
> gpadl_handle)
> unsigned long flags;
> int ret;
>
> - info = kmalloc(sizeof(*info) +
> + info = kzalloc(sizeof(*info) +
> sizeof(struct vmbus_channel_gpadl_teardown), GFP_KERNEL);
> if (!info)
> return -ENOMEM;
> --
> 2.25.1
This change is actually zero'ing more memory than is necessary. Only the
'msg' portion is sent to Hyper-V, so that's all that needs to be zero'ed.
But this code is not performance sensitive, and doing the tighter zero'ing
would add lines of code with no real value. So,
Reviewed-by: Michael Kelley <mikelley@xxxxxxxxxxxxx>
